Mission to Neptune proposed

A group of US researchers have proposed a $3-4 billion mission to Neptune and its largest moon Triton – and intend to make an approach to NASA and the US Congress in 10 years time.

The 4.5 billion km trip would involve a 36-tonne spacecraft, powered by a nuclear fission reactor and ion propulsion system, acting as the mothership, carrying a batch of probes.

Bernie Bienstock, a robotic systems project manger Boeing, is heading the 30 year mission to send only the second spacecraft to visit Neptune, following Voyager 2’s flyby in 1989.

‘It’s probably like an 18-year mission but then there’s all the lead time – another 10 years to do all the selling to Congress and NASA, and do all the detailed engineering design,’ he said to the BBC.

‘You’re looking at about 30 years from beginning to end.’

Bienstock mothership would first approach Triton, where it would drop a lander in the path of a landing on the surface.

It would have to be a heavy lander, using propulsion to slow it down as it approaches the ground, as opposed to parachutes.

‘The probe would have a mass of about 500kg – 65 per cent of that is a propulsion system to slow you down so you don’t crash,’ he explained. ‘There is a very thin atmosphere on Triton but there’s not enough for parachutes to slow you down.

‘You’ve got a lot of engineering overhead just to deliver the science package.’

The mothership would carry on towards Neptune with two more landers targeting similar landings for sampling chemicals and materials – as well as beaming back images via the mothership.